Re: Delegations
In article mailman.564.1351726720.11945.bind-us...@lists.isc.org, Mark Andrews ma...@isc.org wrote: In message 5091adef.1040...@dougbarton.us, Doug Barton writes: On 10/31/2012 03:56 PM, Mark Andrews wrote: You are equating a practice that was techically wrong, and known to be wrong from the get go, with one that has never been techically wrong. Yes, I'm making exactly the same judgment that typical users make. It works, so it must be Ok. The fact that we (experts) can get away with something, whether it's technically right/wrong/indifferent not withstanding, doesn't mean that it's good advice for the average user. Doug Putting in delegations where they are not needed introduces additional work and more places that can go wrong. And also (he said very quietly indeed after delurking) increases the granularity of management. Being able to reload or work on a small (sub)zone rather than a large one can have advantages, which of course have to be balanced with the extra effort involved in setting such a system up. YPYMAYTYP. Sam -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
YPYMAYTYP Zero results from my favorite search engine -- congratulations. ;-) -JP ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
In article mailman.571.1351768172.11945.bind-us...@lists.isc.org, Jan-Piet Mens jpmens@gmail.com wrote: YPYMAYTYP Zero results from my favorite search engine -- congratulations. ;-) Thank you. Try YPYMAYTYC but I was thinking pick. Sam -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
On Oct 31, 2012, at 4:02 PM, Doug Barton wrote: On 10/31/2012 03:56 PM, Mark Andrews wrote: You are equating a practice that was techically wrong, and known to be wrong from the get go, with one that has never been techically wrong. Yes, I'm making exactly the same judgment that typical users make. It works, so it must be Ok. The fact that we (experts) can get away with something, whether it's technically right/wrong/indifferent not withstanding, doesn't mean that it's good advice for the average user. I must disagree with my learned colleague here. Introducing the extra subzone for the current subdomain also introduces extra work if DNSSEC is later introduced. It can also cause as many problems as it solves even in the absence of DNSSEC. As for the possibility of administrator error in the future, and making things futureproof, I would assert that stumbling when bad assumptions cause problems is the quickest way to learn the proper rules of DNS. Designing a system to match the possible wrong-headed assumptions of future admins results in a system akin to Microsoft's DNS snap-in for MMC, whereby users then develop mistakes in their thinking about how DNS works and therefore are unable to properly troubleshoot and fix real problems when they occur. I would prefer to promote a correct understanding of the actual rules of DNS. Chris Buxton BlueCat Networks ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
On 31/10/12 17:12, wbr...@e1b.org wrote: I have a zone file for example.org that has entries for a subdomain l2.example.org like this: vpn.l2 IN A10.1.2.3 Now they want to add a subdomain below l2, ie. ad.l2.eboces.org with hosts such as dc.ad.l2.eboces.org You terminology is a bit confusing here. subdomain is imprecise. Specify what *zones* you want, and where you want the delegations, and it should be easy to see what will work and not. example.org SOA www.example.org A - hostname, in example.org zone vpn.l2.example.org A - hostname, still in example.org zone ad.l2.example.org NS - delegation point in example.org zone xx.ad.l2example.org A - glue, *still* in example.org zone ...and of course then the SOA zone contents for ad.l2.example.org In the zone file for example.org, I can add NS and glue records for ad.l2.example.org as this: dc.ad.l2 IN A 10.2.3.4 dr.ad.l2 IN A 10.4.5.6 ad.l2 IN NS dc.ad.l2.example.org. ad.l2 IN NS dr.ad.l2.eboces.org. Will this work, Yes, if I've understood what you want. or do I need to delegate l2.example.org before I can delegate ad.l2.example.org? No. Zone cuts can be at any label inside a zone. ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
Phil Mayers p.may...@imperial.ac.uk wrote: No. Zone cuts can be at any label inside a zone. Provided inside does not include the zone apex :-) Tony. -- f.anthony.n.finch d...@dotat.at http://dotat.at/ Forties, Cromarty: East, veering southeast, 4 or 5, occasionally 6 at first. Rough, becoming slight or moderate. Showers, rain at first. Moderate or good, occasionally poor at first. ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
Phil wrote on 10/31/2012 02:15:16 PM: You terminology is a bit confusing here. subdomain is imprecise. Sorry, I meant it as a piece of the FQDN. Specify what *zones* you want, and where you want the delegations, and it should be easy to see what will work and not. Yes, if I've understood what you want. I think you got it. or do I need to delegate l2.example.org before I can delegate ad.l2.example.org? No. Zone cuts can be at any label inside a zone. Thanks. Waiting for firewall changes tonight to test. Confidentiality Notice: This electronic message and any attachments may contain confidential or privileged information, and is intended only for the individual or entity identified above as the addressee. If you are not the addressee (or the employee or agent responsible to deliver it to the addressee), or if this message has been addressed to you in error, you are hereby notified that you may not copy, forward, disclose or use any part of this message or any attachments. Please notify the sender immediately by return e-mail or telephone and delete this message from your system. ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
On 10/31/2012 10:12 AM, wbr...@e1b.org wrote: I have a zone file for example.org that has entries for a subdomain l2.example.org like this: vpn.l2 IN A10.1.2.3 Now they want to add a subdomain below l2, ie. ad.l2.eboces.org with hosts such as dc.ad.l2.eboces.org As someone else pointed out, you're confusing different terms here. If all you want is to add new host names that have l2.eboces.org in them, you can do that without creating a zone cut. OTOH, if what you want to do is create a new zone at ad.l2.eboces.org because you want to delegate it to _different_ name servers than those authoritative for eboces.org, then yes; your safest bet is to do proper zone cuts at each level. It's perfectly Ok to have the name servers for l2.eboces.org be the same as those for eboces.org, just make sure you move any related records (such as your vpn.l2 above) into the new zone file. It may or may not be strictly necessary to do this depending on everything else you have in the zone, but it's safer in the long term to do it this way. hope this helps, Doug In the zone file for example.org, I can add NS and glue records for ad.l2.example.org as this: dc.ad.l2 IN A 10.2.3.4 dr.ad.l2 IN A 10.4.5.6 ad.l2 IN NS dc.ad.l2.example.org. ad.l2 IN NS dr.ad.l2.eboces.org. Will this work, or do I need to delegate l2.example.org before I can delegate ad.l2.example.org? ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
On 10/31/2012 06:51 PM, Doug Barton wrote: It may or may not be strictly necessary to do this depending on everything else you have in the zone, but it's safer in the long term to do it this way. Are you suggesting it's best of the OP creates l2.example.com as a sub-zone? Why it this necessary / safer? ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
On 10/31/2012 5:15 PM, Phil Mayers wrote: On 10/31/2012 06:51 PM, Doug Barton wrote: It may or may not be strictly necessary to do this depending on everything else you have in the zone, but it's safer in the long term to do it this way. Are you suggesting it's best of the OP creates l2.example.com as a sub-zone? Why it this necessary / safer? I know of at least 2 commerically-available DNS maintenance systems that, by default, do not allow what they call dotted hostnames, by which they mean a name which is at least 2 labels below a zone cut, e.g. foo.bar in the example.com zone. Their underlying assumption seems to be that *every* level of the hierarchy will, in the usual/typical/default case, be delegated. I don't agree with this assumption in the slightest, but some people are afraid of changing default behaviors... - Kevin ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
On Oct 31 2012, Phil Mayers wrote: On 10/31/2012 06:51 PM, Doug Barton wrote: It may or may not be strictly necessary to do this depending on everything else you have in the zone, but it's safer in the long term to do it this way. Are you suggesting it's best of the OP creates l2.example.com as a sub-zone? Why it this necessary / safer? It certainly isn't necessary. We have plenty of zone cuts more than one label deep into the parent zone. And of course such delegations are *extremely* common in the reverse lookup trees, with the IPv6 one probably providing records for the number of labels between cuts. I don't see how safer would apply, either. -- Chris Thompson Email: c...@cam.ac.uk ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
On Oct 31 2012, Kevin Darcy wrote:
[...snip...]
I know of at least 2 commerically-available DNS maintenance systems
that, by default, do not allow what they call dotted hostnames, by
which they mean a name which is at least 2 labels below a zone cut, e.g.
foo.bar in the example.com zone. Their underlying assumption seems
to be that *every* level of the hierarchy will, in the
usual/typical/default case, be delegated.
I don't agree with this assumption in the slightest, but some people are
afraid of changing default behaviors...
What default behavior? The default behavior of (seriously) defective
DNS maintenance systems? (You wouldn't like to name-and-shame, I suppose?)
The end-point of that sort of logic is that, for example, the SRV record
for _someservice._tcp.somename.example.com has to have separate zones
for somename.example.com and _tcp.somename.example.com, probably
containing nothing but the names mentioned. I've seen people actually
do this, and it's painful to watch.
We were never in that mess as regards the DNS itself, but we did have
an IP registration database that delegated control over names on the basis
of a domain part taken to be all but the first label. It was hard work
to change it to allow the domain part for authorisation purposes to be
any trailing set of labels, but by ${DEITY?} it was necessary!
--
Chris Thompson
Email: c...@cam.ac.uk
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Re: Delegations
On 10/31/2012 03:22 PM, Chris Thompson wrote: On Oct 31 2012, Kevin Darcy wrote: [...snip...] I know of at least 2 commerically-available DNS maintenance systems that, by default, do not allow what they call dotted hostnames, by which they mean a name which is at least 2 labels below a zone cut, e.g. foo.bar in the example.com zone. Their underlying assumption seems to be that *every* level of the hierarchy will, in the usual/typical/default case, be delegated. I don't agree with this assumption in the slightest, but some people are afraid of changing default behaviors... What default behavior? The default behavior of (seriously) defective DNS maintenance systems? (You wouldn't like to name-and-shame, I suppose?) The end-point of that sort of logic is that, for example, the SRV record for _someservice._tcp.somename.example.com has to have separate zones for somename.example.com and _tcp.somename.example.com, probably containing nothing but the names mentioned. I've seen people actually do this, and it's painful to watch. Chris, I specifically asked the OP if they wanted a zone cut at the higher level, or if they were just looking for multi-dot names. So this particular argumentum ad absurdum is particularly inappropriate. We used to say that you didn't need to do a delegation if the subzone was going to be hosted on the same auth. name server either, and then along came DNSSEC and lots of people with systems that weren't breaking any rules are suddenly dealing with strange error messages. So sure, the OP could probably get away with it even without doing a zone cut at the middle level. But I stand by my assertion that for maximum future-proofing they're safer with it than without. Doing the zone cut costs them almost nothing now, and may save time/effort/energy down the road. Doug ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
In message 5091a8bc.70...@dougbarton.us, Doug Barton writes: On 10/31/2012 03:22 PM, Chris Thompson wrote: On Oct 31 2012, Kevin Darcy wrote: [...snip...] I know of at least 2 commerically-available DNS maintenance systems that, by default, do not allow what they call dotted hostnames, by which they mean a name which is at least 2 labels below a zone cut, e.g. foo.bar in the example.com zone. Their underlying assumption seems to be that *every* level of the hierarchy will, in the usual/typical/default case, be delegated. I don't agree with this assumption in the slightest, but some people are afraid of changing default behaviors... What default behavior? The default behavior of (seriously) defective DNS maintenance systems? (You wouldn't like to name-and-shame, I suppose?) The end-point of that sort of logic is that, for example, the SRV record for _someservice._tcp.somename.example.com has to have separate zones for somename.example.com and _tcp.somename.example.com, probably containing nothing but the names mentioned. I've seen people actually do this, and it's painful to watch. Chris, I specifically asked the OP if they wanted a zone cut at the higher level, or if they were just looking for multi-dot names. So this particular argumentum ad absurdum is particularly inappropriate. We used to say that you didn't need to do a delegation if the subzone was going to be hosted on the same auth. name server either, and then along came DNSSEC and lots of people with systems that weren't breaking any rules are suddenly dealing with strange error messages. Adding a child zone without adding the delegating NS records was always a bad idea. Such instruction also usually contained the caveat this is technically wrong and will cause issues if you ever have machines that do not host both zones but you can get away with it. Nameserver also used to merge zone contents so that AXFR included the NS records from the child zone. So sure, the OP could probably get away with it even without doing a zone cut at the middle level. But I stand by my assertion that for maximum future-proofing they're safer with it than without. Doing the zone cut costs them almost nothing now, and may save time/effort/energy down the road. You are equating a practice that was techically wrong, and known to be wrong from the get go, with one that has never been techically wrong. Doug ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: Delegations
In message 5091adef.1040...@dougbarton.us, Doug Barton writes: On 10/31/2012 03:56 PM, Mark Andrews wrote: You are equating a practice that was techically wrong, and known to be wrong from the get go, with one that has never been techically wrong. Yes, I'm making exactly the same judgment that typical users make. It works, so it must be Ok. The fact that we (experts) can get away with something, whether it's technically right/wrong/indifferent not withstanding, doesn't mean that it's good advice for the average user. Doug Putting in delegations where they are not needed introduces additional work and more places that can go wrong. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
